Sealed stator submerged electric fuel pump



J. L. HAGGERTY 2,972,308

SEALED sTAToE suEMERGED ELECTRIC FUEL PUMP Filed March 12, 1957 2 sheets-sheet 1 EJE.

Feb. 2l, 1961 Feb. 2l, 1961 J. L. HAGGERTY MP SEALED sTAToR suBMERGED ELECTRIC FUEL PU 2 Sheets-Sheet 2 Filed March 12, 1957 l .gg y@ `W iL/5 SEALED STATOR SUBMERGED ELECTRIC FUEL PUMP lohn L. Haggerty, Lyndhurst, Ohio, assigner to Thumpn son Ramo Wooldridge Inc., a corporation of Ohio Filed Mar. 12, 1957, Ser. N0. 645,449

Claims. (Cl 10S- 87) This invention relates generally to electrically operated pumps and more particularly relates to a pump which has a special utility when employed as a submerged fuel pump in an aircraft fuel system and wherein the rotor and stator of the electric motor of the pump are isolatably sealed and separated, thereby to isolate the electrical systern of the pump from the fluid system of the pump.

It is an object of the present invention to provide an improved pump which is electrically powered and whereby the motor enclosure is constructed to afford isolation of the electrical system from the fluid system.

It is another object of the present invention to provide a submerged fuel pump incorporating the principles of the present invention whereby high temperature insulation may be effectively utilized.

Another object of the present invention is to provide -a submerged fuel pump constructed to eliminate lead Wire seals and shaft seals.

Yet another object of the present invention is to provide a Sealed stator submerged fuel pump which effectively utilizes an immersed rotor cooling system.

Another object of the present invention is to provide a submerged fuel pump which effectively retains fuel-lubricated carbon bearings Without interfering with the electrical system of the pump.

A further object is to provide a submerged pump which effectively pumps water or watencontaminated fuel without harmful effect on the pump.

Still another object of the present invention is to provide an electrically powered pump wherein contamination of the winding end turns is prevented.

Yet another object of the present invention is to provide a pump wherein the use of a check valve is permitted to retain fuel on dry runs for cooling and lubricating purposes,

A further object of the present invention is to provide a pump wherein a coolant of high dielectric strength may be utilized in the electrical cavity and combine with a lead wire seal to permit higher temperature operation of the pump.

Many other features, advantages and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description which follows and the accompanying sheets of drawings in which a preferred structural embodiment of a pump incorporating the principles of the present invention is sho-wn by way of illustrative example.

On the drawings:

Figure 1 is a cross-sectional view with parts shown in elevation of a submerged electric fuel pump incorporating the principles of the present invention with parts removed forthe sake of clarity and with p-arts shown in elevation;

vFigure 2 is an enlarged fragmentary cross-sectional View similar in orientation to Figure 1 but showing additional `details of construction of the novel features of the present invention;

Figure 3 is a view similar to Figure 2 but showing an alternative structure of the seal barrier provided in ac- Sii 2,972,308 Patented Feb. 2l, 1961 cordance with the principles of the present invention; and

Figure 4 is a View similar to Figures 2 and 3 but showing another variant of the seal barrier provided in accordance with the principles of the present invention.

Although the principles of the present invention are of general utility, a particularly useful application is found when embodied in a submerged fuel pump adapted to be mounted on one wall of an aircraft fuel cell. Thus, there is shown in Figure l a fuel cell 10 having an opening in one Wall thereof in which is mounted the pump of the present invention indicated generally by the reference numeral 11. The pump includes a housing which consists of connected together casing sections, the casing being idicated generally at 12 and including a lower portion 13 which closes the opening in the fuel cell 10 and which is provided with a boss 14 forming a so-called in-out coupling by means of which the discharge of the pump may be directed through `an outside outlet 16 if it is desired to connect the pump to a conduit outside of the fuel cell, or an inside outlet 1.7, if it is desired to discharge fluid through a conduit extending through the interior of the fuel cell 10.

The bottom section 13 of the casing also has formed therein a center inlet 18 which communicates with the` interior of fuel cell 10 as at 19, a suitable filter screen being indicated at 26 encircling a sump 21 formed at the bottom of the pump structure.

inwardly adjacent the center inlet 18 and within the bottom section 13 of the casing there is provided a pumping chamber 22 in which is rotated an impeller 23. The impeller 23 has a plurality of circumferentially spaced blades 24 for advancing fluid axially from the center inlet 1S whereupon radial pumping blades indicated at 26 discharge the fluid radially outwardly into a volute 27 con nected by a cored passage leading to the outlet portion of the boss 14.

The center section of the casing is indicated at 28 and includes an inwardly extending boss 29 formed with a bore Sii to receive a sleeve bearing 31.

rl`he upper section of the casing is indicated at 32 and is generally cup-shaped in configuration, having an end wall 33. Extending axially inwardly from the end wall 33 is a boss 34 surrounding an opening 36 in which is received a sleeve bearing 37.

A shaft 38 has spaced bearing `areas indicated at 39 and 40, respectively, supported in the sleeve bearings 31 and 37, thereby rotatably journaling the shaft in the casing. The impeller 23 has a hub 41 which is suitably apertured to receive one end of the shaft 3S, suitable fastening means being indicated at 42 to connect the impeller 23 in corotatable assembly with the shaft 38.

The hub 4l has an upstanding circumferentially extending wall 43 which is closely spaced to a diffusion ring 44 carried by the central section 28 of the casing and forming together therewith a throat 46 through which vaporrich fluid is discharged for return to the fuel cell 1t).

in order to drive the impeller 23 rotatably, there is provided an electric motor of the induction-type and more specifically a squirrel cage motor indicated generally at The motor 55j includes a squirrel cage rotor 5l characterized in the usual manner by a plurality of circumferentially spaced bars 52 short-circuited by end rings indicated at S3 and 54, respectively, although it will be understood that the bars and the end rings may be made as an integral metal casting, if desired.

The motor 50 further includes a stator 56 having upper and lower stator windings indicated at 57 and 53, respectively.

rThe rotor 51 also Ahas a ring 59' having a surface which is engaged by the end of a bearing member 60 carried by the central section 28 of thecasing and spaced axially from the bearing sleeve 31.

lt will be noted that the opening 36 in the wall 33 of the upper casing section 32 communicates directly with the interior of the fuel cell 10 and is, therefore, flooded with liquid fuel. Such llooding assists in the cooling and lubrication of the bearing surface 4t) and the bearing sleeve 37. There is also provided in the end wall 33 a passageway 61 by means of which fuel pumped outwardly through the interior of a motor chamber 62 formed in the casing inwardly adjacent the end wall 33, and which is provided for housing the induction motor t), may be vented back to the fuel cell.

it will be further noted that the central section 2S of the casing is provided with a passageway 63 and the bottom section 13 of the casing has an intersecting passageway 64 leading to the volute 27. The passageway 63 intersects a passageway 65 counterbored to form a valve seat 65a seating a ball check valve 65b. When the tank or fuel cell runs dry, there is no pressure in the volute 27 and the check valve 65b Will seal what liquid there is in the motor compartment 68. Thus, if the motor continues operation, the trapped fuel in the motor compartment leaks very slowly through the impeller end bearings at 31. Moreover, if the fuel becomes heated and vaporizes, some lubrication will be effected at the upper bearings 37. Furthermore, the rib around the lower bearings provides a reservoir of fuel which cannot escape, thereby retaining a supply of fuel for creating vapor for lubrication. In normal operation, of course, iluid from the volute 27 passes upwardly through the passageways 64, 63, 65 and into the motor compartment. The sleeve bearings 31 and 37 are conveniently provided of carbon material. Thus, fuel cooling and lubrication of the bearing surfaces is effected and the immersion of the rotor provides cooling which enhances the operation thereof. The rotor 51 includes axially extending passageway 66 which facilitates circulation of iluid between opposite ends of the rotor.

In accordance with the principles of the present invention, the electrical system of the pump is isolated from the fluid system. As shown in Figures 1 and 2, there is provided a generally cylindrical sleeve 67 which is interposed between the stator 56`and the rotor 51. The sleeve 67 thereby divides the motor chamber 62 into an inner rotor compartment 68 and an outer annular stator compartment 69. To insure sealed isolation of the inner and outer compartments 68 and 69, the end of the sleeve 67 is provided with an enlarged annular rib 70 which abuts against the end wall 33. An annular shoulder 71 extends axially inwardly from the wall 33 and is peripherally grooved as at 72 to seat a sealing member '73, the sealing member engaging an adjoining inner surface of the rib 70, thereby to securely seal the inner and outer compartments 68 and 69 at one end of the sleeve 67.

At the opposite end of the sleeve 67, the end is flared slightly as at 74 thereby to permit a ready assembly of the sleeve 67 over a pilot boss 76 formed on the central section 28 of the casing. The boss 76 is peripherally grooved as at 77 to receive a sealing member 78 engaging against an adjoining inner surface of the sleeve 67.y By virtue of such provision, the lower end of the sleeve 67 is securely sealed, thereby completely isolating the inner and outer compartments 68 and 69 and separating the electrical system of the pump from the fluid system thereof.

The casing of the pump, and specifically the central section 28 thereof, is further characterized by the provision of a passageway 79 through which is extended the 'electrical conducting means 80 by means of which the pump 5G is energized. By virtue of the isolation effected by the sleeve 67, it will be appreciated that special Wire seals are not required and the wire passage 70 can be simply and conveniently provided through an ordinary cored passage in the casing sections.

In the embodiment of Figure 3, a sleeve is indicated at 67a and the opposite ends thereof comprise rolled flanges 81 and 82, respectively. It will be noted that the llanges are rolled in opposite directions, the flange 81 being rolled outwardly thereby facilitating assembly of the sleeve 67a over the pilot portion 76a of the casing section 26a. A peripheral groove 77a formed in the pilot portion 76a receives a sealing member 78a which engages an adjoining surface on the inner side of the sleeve 67a.

The flange 82 is rolled inwardly and the casing section 32a is provided with a peripheral groove 72a sealing a sealing member 73a for engaging the outer peripheral surface of the sleeve 67a.

The remaining components of the structure, as shown in Figure 3, are identical to those already described and similar reference numerals with a suilix a have been applied to further illustrate the structure.

1n Figure 4, yet another alternative is shown. In this form of the invention one of the motor laminations 87 is flanged at 86. ln other words, the flanged portion is like a ring member 86 which extends generally axially. The part which extends radially as at 88 (the laminate 87) is sealed to the adjoining stator laminations as an integral part thereof.

The end of the ring 86 is provided with a rolled flange S9 engaging against the end wall 33h.

The seal barrier may be made of any suitable material consonant with` good engineering practice such as the non-metallic material indicated in connection With sleeve 67 and the metallic materials indicated at 67a, 86 and 87.

An axially extending rib 7fa formed on the end wall 33b is peripherally grooved as at '72b and receives a sealing member 73b which engages against an inner surface of the ring 86. By virtue of such provision, the upper electrical winding 57b of the stator 56b is completely isolated.

The lower winding 58b of the stator S617 is similarly isolated by a ilanged end lamination sealed to the stator laminations and bearing the same reference numerals and constructed in the same general manner to cooperate with the pilot portion 76h and the seal ring 78h carried in the groove 77b.

The complete isolation of the electrical system from the fuel system permits the use of high temperature insulation and eliminates lead Wire seals and shaft seals, while retaining the advantages of immersed rotor cooling and fuel lubricated bearings. Moreover, the contamination of winding end turns is prevented and the use of a check valve to retain fuel on dry runs for cooling and lubricating purposes, as described above, is permitted.

It will be understood that a further use of the structure disclosed could be made in utilizing a coolant of a high dielectric strength in the electrical cavity in which event a lead wire seal would be provided to permit high temperature operation of the pump.

Although minor structural modifications might be provided by those versed in the art, it should be understood that I Wish to embrace within the scope of the patent warranted hereon all such modifications as reasonably and properly come Within the scope of my contribution to the art.

1 claim as my invention:

l. A pump comprising a casing having formed therein a pumping chamber and a motor chamber axially adjacent thereto, said pumping chamber having an inlet and an outlet, rotary fluid displacement means in said pumping chamber for moving lluid from the inlet to the outlet, a rotor in said motor chamber having a shaft extending axially thereof and connected to said rotary lluid displacement means, a stator surrounding said rotor and having electrical conductor wires connected thereto for energization of said motor, means forming a sealed' barrier between said rotor and said stator whereby the fuel and electrical systems of the pump are isolated from one another, said means forming a sealed barrier cornprising a sleeve member of greater length than said stator extending between said rotor and said stator to divide said motor chamber into an inner rotor compartment' and an outer annular stator compartment, said casing having a wiring passage formed therein opening into said stator compartment, a passage formed in said casing interconnecting the pu'mp and motor chambers, a valve seat in said passage, and va check valve on said valve Seat closing said passage to retain fiuid in said motor chamber but opening to admit iiuid into said motor chamber from said pumping chamber in response to pumpgenerated pressures, thereby to cool and lubricate the rotor on both normal and dry runs.

2. An electrically operated pump comprising a casing having a bore formed therein and a plurality of bosses in said bore forming bearing supports, one portion of said bore being enlarged to provide a pumping chamber, an adjacent portion of said bore being enlarged to provide a motor chamber, rotary fluid displacement means in said pumping chamber, a rotor in said motor chamber, a shaft extending through said bosses and connected to said rotor and to said rotary uid displacement means, carbon bearing sleeves in said bosses journaling said shaft, said sleeves being lubricated by the pumping fluid, said rotor having passages formed therein affording communication of pumping uid between the bearing sleeves on opposite sides thereof, sealing means in 'said motor chamber dividing said motor chamber into a rotor compartment and into an isolated compartment for receiving the stator windings of the stator, circuit means in said casing extending into said isolated compartment, whereby the electrical system of the pump is completely separated from the uid system of the pump, a passage formed in said casing interconnecting the pump and motor chambers, a valve seat in said passage and a check valve responsive to .pump-'generated pressures to admit fluid from said pump chamber into k'said motor chamber and retaining fluid in said motor chamber for cooling and operating said rotor during `dry run operation.

3. A pump comprising a casing having formed therein a pumping chamber and a motor chamber axially adjacent thereto, said pumping chamber having an inlet and 'an outlet, rotary fluid vdisplacement means in said pumping chamber for moving fluid from the inlet to the outlet, a rotor in said motor chamber having a shaft extending axially thereof and connected to said rotary iiuid displacement means, a stator Vsurrounding said rotor and having electrical conductor wires connected thereto for energization of said motor, sealing means forming a barrier `between said rotor and said stator to divide the motor chamber into a rotor compartment and a stator compartment, thereby isolating the fuel and electrical systems of the pump from one another, said casing having a wiring passage formed therein opening into said stator compartment, a passage formed in said casing interconnecting the pump and motor chambers, a valve seat in said passage, and a check valve on said valve seat closing said passage to retain huid in said motor chamber but opening to admit iiuid into said motor chamber from said pumping chamber in response to pump-generated pressures, thereby to cool and lubricate the rotor on both normal and dry runs.

4. A pump comprising a casing having formed therein a pumping chamber and a motor chamber axially adjacent thereto, said pumping chamber having an inlet and an outlet, rotary fluid displacement means in said pumping chamber for moving fluid from the inlet to the outlet, a rotor in said motor chamber having a shaft extending axially thereof and connected to said rotary Huid displacement means, a stator surrounding said rotor and having electrical `conductor Wires connected thereto for energization of said motor, sealing means forming a barrier between said rotor and said stator to divide the motor chamber into a rotor compartment and a stator compartment, thereby isolating the fuel and electrical systems of the pump from one another, said sealing means comprising a cylindrical sleeve and sealing rings in said casing engaging an adjoining portion of said cylindrical sleeve axially inwardly of the opposite ends thereof, said casing having a Wiring passagek formed therein opening into said stator compartment, a passage formed in said casing interconnecting the pump and motor chambers, a valve seat in said passage, and a check valve on said valve seat closing said passage to retain fluid in said motor chamber but opening to admit fluid into said motor chamber from said pumping chamber in response to pump-generated pressures, thereby to cool and lubricate the rotor on both normal and dry runs.

5. A pump comprising a casing having formed therein a pumping chamber and a motor chamber axially adjacent thereto, said pumping chamber having an inlet and an outlet, rotary fluid displacement means in said pumping chamber for moving uid from the inlet to the outlet, a rotor in said motor chamber having a shaft extending axially thereof and connected to said rotary huid displacement means, a stator surrounding said rotor and having electrical conductor Wires vconnected thereto for energization of said motor, sealing means forming a barrier between said rotor and said stator to divide the motor chamber into a rotor compartment and a stator compartment7 thereby isolating the fuel and electrical systems of the pump from one another, said sealing means comprising a flanged ring at opposite ends of said stator sealed to the adjoining portions of the stator, said casing having a wiring passage formed therein opening into said stator compartment, a passage formed in said casing interconnecting the pump and motor chambers, `a valve seat in said passage, and a check valve on said valve seat closing said passage to retain fluid in said motor chamber but opening to admit fluid into said motor chamber from said pumping chamber in response to pumpgenerated pressures, thereby to cool and lubricate the rotor on both normal and dry runs.

6. A pump comprising a casing having formed therein a pumping chamber and a motor chamber axially adjacent thereto, said pumping chamber having an inlet and an outlet, rotary fluid displacement means in said pumping chamber for moving fluid from the inlet to the outlet, a rotor in said motor chamber having a shaft extending axially thereof and connected to said rotary fluid displacement means, a stator surrounding said rotor and having electrical conductor wires connected thereto for energization of said motor, sealing means forming a barrier between said rotor and said stator to divide the motor chamber into a rotor compartment and a stator compartment, thereby isolating the fuel and elecrical systems of the pump from one another, said stator comprising a plurality of laminations and said sealing means comprising one of the laminations of said stator being formed as a anged ring at the opposite ends of the stator and being sealed to the adjoining laminations, said casing having a wiring passage formed therein opening into said stator compartment, a passage formed in said casing interconnecting the pump and motor chambers, a Valve seat in said passage, and a check valve on said valve seat closing said passage to retain fluid in said motor chamber but opening to admit huid into said motor chamber from said pumping chamber in response to pumpgenerated pressures, thereby to cool and lubricate the rotor on both normal and dry runs.

7. A pump comprising a casing having formed therein a pumping chamber and a motor chamber axially adjacent thereto, said pumping chamber having an inlet and an outlet, rotary fluid displacement means in said pumping chamber for moving fluid from the inlet to the outlet, a rotor in said motor chamber having a shaft extending axially thereof and connected to said rotary uid displacement means, a stator surrounding said rotor and having electrical conductor wires connected thereto for energization of said motor, sealing means forming a barrier between said rotor and said stator to divide the motor chamber into a rotor compartment and a stator compartment, thereby isolating the fuel and electrical systems of the pump from one another, said sealing means comprising a sleeve extending through the motor compartment and being disposed concentric to the motor chamber axis to divide the chamber into an inner cylindrical rotor compartment and an annular outer stator compartment, said casing having a wiring passage formed therein opening into said stator compartment, a passage formed in said casing interconnecting the pump and motor charnbers, a valve seat in said passage, and a check valve on said valve seat closing said passage to retain uid in said motor chamber but opening to admit fluid into said motor chamber from said pumping chamber in response to pump-generated pressures, thereby to cool and lubricate the rotor on both normal and dry runs.

8. A pump comprising a casing having formed therein a pumping chamber and a motor chamber axially adjacent thereto, said pumping chamber having an inlet and an outlet, rotary uid displacement means in said pumping chamber for moving fluid from the inlet to the outlet, a rotor in said motor chamber having a shaft eX- tending axially thereof and connected to said rotary fluid displacement means, a stator surrounding said rotor and having electrical conductor wires connected thereto for energization of said motor, sealing means forming a barrier between said rotor and said stator to divide the motor chamber into a rotor compartment and a stator compartment, thereby isolating the fuel and electrical systems of the pump from one another, said sealing means comprising a sleeve having rolled flanges at opposite ends thereof for engaging an adjoining end wall and an adjoining portion of said casing, respectively, and sealing members in said casing engaging an adjoining portion of said sleeve axially inwardly of said flanges, said casing having a wiring passage formed therein opening into said stator compartment, a passage formed in said casing interconnecting the pump and motor chambers, a valve seat in said passage, and a check valve on said valve seat closing said passage to retain uid in said motor chamber but opening to admit fluid into said motor chamber from said pumping chamber in response to pump-generated pressures, thereby to cool and lubricate the rotor on both normal and dry runs.

9. A pump comprising a casing having formed therein a pumping chamber and a motor chamber axially adjacent thereto, said pumping chamber having an inlet and an outlet, rotary uid displacement means in said pumping chamber for moving uid from the inlet to the outlet, a rotor in said motor chamber having a shaft extending axially thereof and connected to said rotary uid displacement means, a stator comprising upper and lower laminated stator windings surrounding said rotor and having electrical conductor wires connected thereto for energization of said motor, and means forming a sealed barrier between said rotor and said stator whereby the fuel and electrical systems of the pump are isolated from one another, said means forming a sealed barrier comprising one of the stator windings forming a flanged ring at each of the opposite ends of said stator and being sealed to the adjoining laminated windings for sealing the stator section where the laminated windings thereof would be exposed to pumping uid.

10. A pump comprising a casing having an end wall, a motor chamber inwardly adjacent said end wall, a pumping chamber inwardly adjacent said motor chamber, bearing means in said casing, a rotary shaft journaled in said bearing means and having rotary fluid displacement means rotatable in said pump chamber and a rotor rotatable in said motor chamber, a stator in said motor chamber including a stator winding having electrical connections extending outwardly of said casing, and a flanged ring at opposite ends of said stator forming together with said casing an enclosure for the stator windings, thereby to isolate the electrical and fluid systems of the pump, said stator comprising a plurality of laminations and said anged ring comprising a flanged end lamination sealed to the adjoining laminations of said stator.

References Cited in the tile of this patent UNITED STATES PATENTS 1,269,909 Cooper June 18, 1918 1,974,183 Gunderson Sept. 18, 1934 1,974,678 Lafont Sept. 25, 1935 2,517,233 Peters Aug. 1, 1950 2,537,310 Lapp Jan. 9, 1951 2,603,161 Lloyd July l5, 1952 2,649,049 Pezzillo et al Aug. 18, 1953 2,673,026 Gerteis Mar. 23, 1954 2,722,892 French Nov. 8, 1955 2,741,990 White Apr. 17, 1956 2,762,311 Litzenberg Sept. 11, 1956 2,786,952 Pleuger Mar. 26, 1957 2,796,835 White Jan. 25, 1957 2,814,254 Litzenberg Mar. 26, 1957 FOREIGN PATENTS 155,823 Sweden June 14, 1956 304,137 Switzerland Mar. 1, 1955 485,270 Great Britain May 17, 1938 562,925 Great Britain July 21, 1944 

